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Common Food Allergy Triggers and Where They Hide

Most people have a reaction to food from time to time. Dip into salsa or spicy Indian food, and your nose starts running. Maybe you get gas from eating beans or headaches from wine. If you're lactose intolerant, you likely get diarrhea if you eat cheese or milk. These are food sensitivities or intolerances, and they are not caused by the immune system.

A food allergy is different. When you're allergic to a food, the immune system reacts abnormally to that specific food. Allergic symptoms can range from a mild skin rash or itchy eyes to a more serious, deadly reaction called anaphylaxis.

Common Food Allergy Symptoms

If you have anaphylactic reactions to certain foods, you probably know it. People who have had anaphylactic reactions to a food should wear a medical alert bracelet or necklace. They should always carry two syringes of epinephrine (adrenaline) and be prepared to inject it if they think they are having a food reaction.

Mild symptoms are more difficult to tie to specific foods. You may get a skin rash, hives, or eczema. Perhaps you feel nauseous, get cramps, vomit, or have diarrhea. Food allergies can even trigger common hay fever symptoms like a runny nose, sneezing, and itchy, watery eyes.

In highly allergic people, even tiny amounts of a food allergen (for example, 1/44,000 of a peanut kernel) can prompt an allergic reaction. Less sensitive people, however, may be able to eat small amounts of the food to which they are allergic.

To help spot hidden food triggers, look over this list. See where they lurk in common grocery store products.

Foods That Cause Allergies

Almost any food can trigger an allergy, but these are most common ones:

  • Milk (mostly in children)
  • Eggs
  • Peanuts
  • Tree nuts (like walnuts, almonds, pine nuts, brazil nuts, and pecans)
  • Soy
  • Gluten (found in wheat, barley, rye, and oats)
  • Fish (mostly in adults)
  • Shellfish (mostly in adults)

Avoiding a problem food is the key to controlling food allergies, but it isn't always easy. Milk, eggs, and nuts may be hidden as ingredients in other foods. Most baked goods, like cakes and cookies, contain eggs and/or nuts. Water-packed tuna may have nonfat dry milk added in. Soybean oil may be hidden in a salad dressing. A hot dog may contain milk protein. That's why reading food labels is very important. 

However, food labels don't tell the whole story. Natural flavors like pineapple, milk casein, or hydrolyzed soy protein may be used in microwave popcorn, for example -- yet you won't see them on the ingredient list. You'll see words like "flavoring" or "natural flavoring." Words like "emulsifier" or "binder" can also hide the fact that soy or egg is in the product. If you have a food allergy, it's important to get familiar with these types of terms.

Here's a brief overview to help you make good decisions at the grocery store. While these lists are not complete, they cover the essentials. If you have questions about any product, call the manufacturer. The customer service department should be able to help -- or the quality assurance officer.

WebMD Medical Reference

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